Bulletin Y-Pattern

1. The body/bonnet threaded connection is designed to support the full longitudinal stress induced by the operating pressure. A failure of the joint would not occur merely as the result of a seal weld failure.

2. The body/bonnet threads are a quality fit to ensure that the valve operating torques are “frictionally resisted” by the connection; therefore, operating stresses are not imposed on the seal welds.

3. The Vogt seal weld design is subject only to circumferential stress, which is induced by the operating pressure.

4. Many other bonnet weld designs are subject to combined stresses. The Vogt design uniquely minimizes the stresses on the seal weld.